Internal choices are weaker than those dictated by the outside world

Publication date:
Feb 11, 2009 4:04:13 PM

The underlying
sense of being in control of our own actions is challenged by new research from
UCL (University College London) which demonstrates that the choices we make
internally are weak and easily overridden compared to when we are told which
choice to make.

The
research, which is published today in Cerebral
Cortex, is one of the first neuroscientific studies to look at changing one’s
mind in situations where the initial decision was one’s own ‘free choice’. Free
choices can be defined as actions occurring when external cues are largely
absent – for example, deciding which dish to choose from a restaurant menu.

The
researchers asked study participants to choose which of two buttons they would
press in response to a subsequent signal, while their brain activity was
recorded using EEG (electroencephalogram). Some choices were made freely by the
volunteers and other choices were instructed by arrows on a screen in front of
them. The volunteers’ choices were occasionally interrupted by a symbol asking
them to change their mind, after they had made their choice, but before they
had actually pressed the button.

First
author Stephen Fleming, UCL Institute of Neurology, said: “When people had
chosen for themselves which action to make, we found that the brain activity involved
in changing one’s mind, or reprogramming these ‘free’ choices was weak, relative
to reprogramming of choices that were dictated by an external stimulus. This
suggests that the brain is very flexible when changing a free choice – rather
like a spinning coin, a small nudge can push it one way or the other very
easily.

“The implication
is that, despite our feelings of being in control, our own internal choices are
flexible compared to those driven by external stimuli, such as a braking in
response to a traffic light. This flexibility might be important - in a dynamic
world, we need to be able to change our plans when necessary.”

Professor Patrick
Haggard, UCL Institute of Cognitive Neuroscience, added: “Our study has two
implications for our understanding of human volition. First, our brains contain
a mechanism to go back and change our mind about our choices, after a choice is
made but before the action itself. Our internal decisions are not set in stone,
but can be re-evaluated right up to the last moment. Second, changing an
internal choice in this way seems to be easier than changing a choice guided by
external instructions.

“We often think
about our own internal decisions as having the strength of conviction, but our
results suggest that the brain is smart enough to make us flexible about what
we want. The ability to flexibly adjust our decisions about what we do in the
current situation is a major component of intelligence, and has a clear
survival value.”

This
research was funded by the Economic and Social Research Council (ESRC), with
additional support from the Wellcome Trust. Stephen Fleming was funded by a
Medical Research Council (MRC) doctoral studentship.

2.) The
paper ‘When the Brain Changes its Mind: Flexibility of Action Selection in Instructed
and Free Choices’ is published online ahead of print in Cerebral Cortex, doi:10.1093/cercor/bhn252. For advance copies
please contact UCL Media Relations. Please
acknowledge Cerebral Cortex as a source in any articles.

3.) This
study was carried out by researchers from UCL, University Medical Center
Utrecht and Stuivenberg
Hospital.